Photoacid generator and photoresist comprising same

ABSTRACT

A photoacid generator compound has the formula (I):
 
[A-(CHR 1 ) p ] k -(L)-(CH 2 ) m —(C(R 2 ) 2 ) n —SO 3   − Z +   (I)
 
wherein A is a substituted or unsubstituted, monocyclic, polycyclic, or fused polycyclic C 5  or greater cycloaliphatic group optionally comprising O, S, N, F, or a combination comprising at least one of the foregoing, R 1  is H, a single bond, or a substituted or unsubstituted C 1-30  alkyl group, wherein when R 1  is a single bond, R 1  is covalently bonded to a carbon atom of A, each R 2  is independently H, F, or C 1-4  fluoroalkyl, wherein at least one R 2  is not hydrogen, L is a linking group comprising a sulfonate group, a sulfonamide group, or a C 1-30  sulfonate or sulfonamide-containing group, Z is an organic or inorganic cation, p is an integer of 0 to 10,k is 1 or 2, m is an integer of 0 or greater, and n is an integer of 1 or greater. A precursor compound to the photoacid generator, a photoresist composition including the photoacid generator, and a substrate coated with the photoresist composition, are also disclosed.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to provisional U.S. Application No.61/541,764, filed on Sep. 30, 2011, the content of which is incorporatedherein by reference in its entirety.

BACKGROUND

Advanced lithographic techniques such as 193 nm immersion lithographyhave been developed to achieve high quality and smaller feature sizes inmicrolithography processes, for purposes of forming ever-smaller logicand memory transistors. It is important to achieve both smaller criticaldimension (CD) in the imaged photoresist used in the microlithographyprocess, and for the photoresists to provide both the lowest line edgeroughness (LER) and line width roughness (LWR), while still retaininggood process control tolerances such as high exposure latitude (EL) anda wide depth of focus (DOF).

To meet the challenges for resist materials raised by high resolutionlithography, tailor-made photoacid generators (PAGs) with controlledacid diffusion and improved miscibility with polymers are veryimportant. It has been found that the structure of the PAG anion plays acritical role in the overall performance of a photoresist by affectingthe interaction of the photoacid generator with other photoresistcomponents. These interactions, affect the diffusion characteristics ofthe photogenerated acid. PAG structure and size can therefore affect thehomogenous distribution of the PAG in the photoresist film. Imagedphotoresists can exhibit defects such as T-topping, foot formation andnotching/undercut where the PAG is not uniformly distributed within thephotoresist film.

While a variety of photoacid generators (PAGs) used for formulatingphotoresists are found in prior art, such as those disclosed in U.S.Pat. No. 7,304,175, a need remains for photoresist compositionsincluding PAGs having greater diffusion control and attendant propertiessuch as resist profile.

STATEMENT OF INVENTION

One or more of the above and other deficiencies of the prior art may beovercome by a photoacid generator in accordance with the invention,having the formula (I):[A-(CHR¹)_(p)]_(k)-(L)-(CH₂)_(m)—(C(R²)₂)_(n)—SO₃ ⁻Z⁺  (I)wherein A is a substituted or unsubstituted, monocyclic, polycyclic, orfused polycyclic C₅ or greater cycloaliphatic group, R¹ is H, a singlebond, or a substituted or unsubstituted C₁₋₃₀ alkyl group, wherein whenR¹ is a single bond, R¹ is covalently bonded to a carbon atom of A, eachR² is independently H, F, or C₁₋₄ fluoroalkyl, wherein at least one R²is not hydrogen, L is a linking group comprising a sulfonate group, asulfonamide group, or a C₁₋₃₀ sulfonate or sulfonamide-containing group,Z is an organic or inorganic cation, and p is an integer of 0 to 10, kis 1 or 2, m is an integer of 0 or greater, and n is an integer of 1 orgreater.

Also disclosed is a compound having the formula:M⁺⁻O—SO₂—(C(R²)₂)_(n)—(CH₂)_(m)—Xwherein each R² is independently H, F, a C₁₋₄ fluoroalkyl, wherein atleast one R² is not hydrogen, X is a functional group including ahalogen, sulfonate, or carboxylate, M⁺ is an organic or inorganiccation, and m is an integer of 0 or greater, and n is an integer of 1 orgreater.

A photoresist composition comprises an acid-sensitive polymer, and theabove photoacid generator compound of formula (I).

A coated substrate further comprises (a) a substrate having one or morelayers to be patterned on a surface thereof; and (b) a layer of thephotoresist composition which includes the photoacid generator compound,over the one or more layers to be patterned.

DETAILED DESCRIPTION

Disclosed herein is a novel class of photoacid generator compoundshaving a sulfonate or sulfonamide linking group connecting a stericallybulky group with a sulfonate salt. The photoacid generators includesterically bulky groups including cycloaliphatic structures such ascaged alkyl groups. Exemplary such groups include adamantane structures,norbornane structures, fused polycyclic lactones, and other suchstructures. The cycloaliphatic groups are linked to a fluorinatedsulfonate group by a linking group that includes a sulfonate orsulfonamide group.

The photoacid generators provide improved control of acid diffusion andmiscibility with photoresist polymers in photoresist compositions.Improvements in properties such as mask error factor (MEF), and exposurelatitude (EL) are obtained by using the sulfonate and sulfonamide-linkedPAGs.

The photoacid generators disclosed herein include those having theformula (I):[A-(CHR¹)_(p)]_(k)-(L)-(CH₂)_(m)—(C(R²)₂)_(n)—SO₃ ⁻Z⁺  (I)wherein A is a substituted or unsubstituted, monocyclic, polycyclic, orfused polycyclic C₅ or greater cycloaliphatic group. As used herein,“substituted” means including a substituent such as a halogen (i.e., F,Cl, Br, I), hydroxy, amino, thiol, carboxyl, carboxylate, amide,nitrile, thiol, sulfide, disulfide, nitro, a C₁₋₁₀ alkyl, a C₁₋₁₀alkoxy, a C₆₋₁₀ aryl, a C₆₋₁₀ aryloxy, a C₇₋₁₀ alkyl aryl, a C₇₋₁₀ alkylaryloxy, or a combination comprising at least one of the foregoing. Itwill be understood that any group or structure disclosed with respect tothe formulas herein may be so substituted unless otherwise specified, orwhere such substitution would significantly adversely affect the desiredproperties of the resulting structure. Also as used herein, the prefix“halo-” means that the group includes any halogen or combination thereof(F, Cl, Br, I). A preferred halogen is fluorine. Optionally, A furtherincludes a heteroatom including O, S, N, F, or a combination comprisingat least one of the foregoing. For example, where A includes oxygen, thestructure of A can include an ether or lactone moiety, or where Aincludes sulfur, the structure of A can include a sultone or sulfonateor sulfam moiety.

Preferably, A is a fused ring C₅₋₅₀ polycycloaliphatic group, havingeither all carbon in a ring structure, or an internal lactone orsulfonate (sultone) moiety. Preferably, A is a fused ring C₈₋₃₅polycycloaliphatic group. Examples of such groups include adamantanestructures such as 1-or 2-substituted adamantyl, and 1-or 2-substitutedhydroxyadamantyl, norbornene endo lactones or sultones, and other C₆₋₁₀polycyclic lactone or sultone-containing groups.

Also in formula (I), R¹ is H, a single bond, or a substituted orunsubstituted C₁₋₃₀ alkyl group, wherein when R¹ is a single bond, R¹ iscovalently bonded to a carbon atom of A. Each R² is independently H, F,or C₁₋₄ fluoroalkyl, wherein at least one R² is not hydrogen.

Further in formula (I), L is a linking group comprising a sulfonategroup of the formula —O—S(O)₂—, a sulfonamide group, or a C₁₋₃₀sulfonate or sulfonamide-containing group. The sulfonamide group ispreferably of the formula —N(R³)—S(O)₂—, wherein R³ is H, alkyl, aryl,or aralkyl. Thus, L can be, for example, a sulfonate or sulfonamidegroup alone, or a C₁₋₃₀ sulfonate or sulfonamide-containing linkinggroup. L can further optionally comprise a heteroatom comprising O, S,N, F, or a combination comprising at least one of the foregoingheteroatoms.

Z is an organic or inorganic cation. As used herein, “organic cation”includes any cation substituted with carbon at the cationic centerincluding an ammonium salt, a phosphonium salt, an iodonium salt, asulfonium salt, a carbonium salt, an oxonium salt, an organotransitionmetal salt (e.g., salts of carbon-substituted iron, nickel, cobalt,manganese, titanium, copper, molybdenum, zinc, etc.), or an organomain-group metal salt (e.g., salts of carbon substituted aluminum, tin,gallium, antimony, etc.). Preferred organic cations include oniumcations. Preferred onium cations include iodonium or sulfonium cations.Also as used herein, “inorganic cation” means any cation not based oncarbon, such as alkali metal cations (Li, Na, K, Rb, Cs), alkaline earthmetal cations (Ca, Ba, Sr), transition metal cations and complexes, andnon-organic cations of nitrogen, phosphorus, and sulfur.

Further in formula (I), p is an integer of 0 to 10, k is 1 or 2, m is aninteger of 0 or greater, and n are each independently an integer of 1 orgreater. Preferably, m and n are independently integers of from 1 to 10.

Preferably, the photoacid generator includes compounds having theformulas (IIa) or (IIb):A-(CHR¹)_(p)—O—SO₂—(CH₂)_(m)—(C(R²)₂)_(n)—SO₃ ⁻Z⁺  (IIa)A-(CHR¹)_(p)—SO₂—O—(CH₂)_(m)—(C(R²)₂)_(n)—SO₃ ⁻Z⁺  (IIb)wherein A, R¹, R² p, m, n, and Z are as defined for formula (I).

Preferably, in formulas (IIa) and (IIb), R¹ is H, or a substituted orunsubstituted C₁₋₂₀ alkyl group. Each R² is independently H or F,wherein at least the two R² groups nearest the sulfonate are fluorine, pis 0 or 1, m and n are independently integers of from 1 to 4, and Z isan iodonium or sulfonium cation.

Also preferably, the photoacid generator compound includes compoundshaving the formulas (IIIa) or (IIIb):A-(CHR¹)_(p)—N(R³)—SO₂—(CH₂)_(m)—(C(R²)₂)_(n)—SO₃ ⁻Z⁺  (IIIa)A-(CHR¹)_(p)—SO₂—N(R³)—(CH₂)_(m)—(C(R²)₂)_(n)—SO₃ ⁻Z⁺  (IIIb)wherein A, R¹, R² p, m, n, and Z are as defined for formula (I), and R³is H, a C₁₋₂₀ alkyl group, or A-(CHR¹)_(p)—. Where R³ is A-(CHR¹)_(p)—,it will be appreciate that this group may be the same as or differentfrom the other group A-(CHR¹)_(p)—.

Preferably, in formula (IIIa) and (IIIb), R¹ is H, a substituted orunsubstituted C₁₋₅ alkyl group, or a A-(CHR¹)_(p)— group. Each R² isindependently H or F, wherein at least the two R² groups nearest thesulfonate are fluorine, R³ is H or a C₁₋₄ alkyl, p is 0 or 1, m and nare independently integers of from 1 to 4, and Z is an iodonium orsulfonium cation.

Exemplary compounds of formulas (I), (IIa), (IIb), (IIIa) and (IIIb)include those having the formulas (IV) to (XII):

wherein Z is as defined in formula (I).

Preferably, Z is an organic cation based on an organosulfoniumstructure. Preferred such organic cations include those in which Z is acation of the formula (XIII):

wherein R⁴ and R⁵ are independently substituted or unsubstituted C₁₋₂₀alkyl, C₁₋₂₀ fluoroalkyl, C₃₋₂₀ cycloalkyl, C₃₋₂₀ fluorocycloalkyl,C₂₋₂₀ alkenyl, C₂₋₂₀ fluoroalkenyl, C₆₋₂₀ aryl, C₆₋₂₀ fluoroaryl, C₅₋₂₀heteroaryl, C₇₋₂₀ aralkyl, C₇₋₂₀ fluoroaralkyl, C₆₋₂₀ heteroaralkyl,where R⁴ and R⁵ are separate or connected by a single bond, and Ar is aC₅₋₃₀ aromatic-containing group.

More preferred organic cations include those having at least onesubstituted aromatic ring attached to the sulfonium center. Such cationsinclude those of the formulas (XIV), (XV), or (XVI):

wherein R⁴ and R⁵ are independently substituted or unsubstituted C₁₋₂₀alkyl, C₁₋₂₀ fluoroalkyl, C₃₋₂₀ cycloalkyl, C₃₋₂₀ fluorocycloalkyl,C₂₋₂₀ alkenyl, C₂₋₂₀ fluoroalkenyl, C₆₋₂₀ aryl, C₆₋₂₀ fluoroaryl, C₅₋₂₀heteroaryl, C₇₋₂₀ aralkyl, C₇₋₂₀ fluoroaralkyl, or C₆₋₂₀ heteroaralkyl,where R⁴ and R⁵ are separate or connected by a single bond; R⁶, R⁷, R⁸and R⁹ are each independently H, a halogen, C₁₋₂₀ alkyl, C₁₋₂₀fluoroalkyl, C₁₋₂₀ alkoxy, C₁₋₂₀ fluoroalkoxy, C₁₋₂₀ thioalkoxy, C₁₋₂₀fluorothioalkoxy, C₁₋₂₀ alkoxycarbonyl, C₁₋₂₀ fluoroalkoxycarbonyl,C₁₋₂₀ thioalkoxycarbonyl, C₁₋₂₀ fluorothioalkoxycarbonyl, C₃₋₂₀cycloalkyl, C₃₋₂₀ fluorocycloalkyl, C₃₋₂₀ cycloalkoxy, C₃₋₂₀fluorocycloalkoxy, C₂₋₂₀ alkenyl, C₂₋₂₀ fluoroalkenyl, C₆₋₂₀ aryl, C₆₋₂₀fluoroaryl, C₆₋₂₀ aryloxy, C₆₋₂₀ fluoroaryloxy, C₅₋₂₀ heteroaryl, C₅₋₂₀heteroaryloxy, C₅₋₂₀ heteroaryloxy, C₇₋₂₀ aralkyl, C₇₋₂₀ fluoroaralkyl,C₇₋₂₀ aralkyloxy C₇₋₂₀ fluoroaralkyloxy, or C₆₋₂₀ heteroaralkyl, orC₆₋₂₀ heteroaralkyloxy, wherein R⁶, R⁷, R⁸ and R⁹ are each independentlyunsubstituted or further substituted to include an acid-labile group, abase-labile group, or a base-soluble group, and q is an integer of 1 to5, r is an integer of 0 to 3, s is an integer of 0 to 4, t is an integerof 0 to 4, and a is an integer of 0 to 4.

Most preferred cations Z include those of the formula (XVII), (XVIII),(XIX), or (XX):

wherein R¹⁰, R¹¹, R¹² and R¹⁴ are independently H, a halogen, C₁₋₁₀alkyl, C₁₋₁₀ fluoroalkyl, C₁₋₁₀ alkoxy, C₁₋₁₀ fluoroalkoxy, C₃₋₁₀cycloalkyl, C₃₋₁₀ fluorocycloalkyl, C₃₋₁₀ cycloalkoxy, or C₃₋₁₀fluorocycloalkoxy, R¹³ is H, C₁₋₁₀ alkyl, C₁₋₁₀ fluoroalkyl, C₃₋₁₀cycloalkyl, or C₃₋₁₀ fluorocycloalkyl, and a and b are eachindependently 1 or 2.

The above photoresist compounds derive from compounds having the formula(XXI):M⁺⁻O —SO₂—(C(R²)₂)_(n)—(CH₂)_(m)—X   (XXI)wherein each R² is independently H, F, a C₁₋₄ fluoroalkyl, where atleast one R² is not hydrogen, X is a functional group including ahalogen, sulfonate, sulfonamide, or carboxylate, M⁺ is an organic orinorganic cation, and m is an integer of 0 or greater, and n is aninteger of 1 or greater. It will thus be appreciated that the formula of(XXI) includes the substructures of the linking group L in formula (I),and the substructure of the halogenated portion of the superacid salt.

The photoresist compounds can be prepared by the derivatization of acompound of the formula (XXI) by, for example, forming the sulfonic acidhalide of the salt by treatment with a halogenating compound such athionyl or sulfonyl chloride, reaction with the amine or alcohol of ancaged polycyclic aliphatic compound such as a substituted orunsubstituted adamantyl methyl compound, norbornane compound, etc.;forming the sulfonic acid from the functional group (where for example,X is Cl, Br, or I in formula (XXI)) from sodium dithionite (Na₂S₂O₄) andoxidation with a peroxide such as hydrogen peroxide; then cationexchange with an onium salt to form the photoacid generator.

A photoresist composition is also disclosed, which includes themolecular glass compound, a solvent, and a photoacid generator.Optionally the photoresist includes a second acid sensitive polymer, andan amine or amide additive.

The second acid-sensitive polymer may be any polymer suitable forformulating photoresists for use at 193 nm Such acid-sensitive polymersinclude an acid sensitive polymer comprising acid sensitive groups andlactone-containing groups, where the acid sensitive group deprotects abase-soluble group on exposure to acid.

The photoresist composition may further include an amine or amidecompound, referred to herein as a quencher. Quenchers may more broadlyinclude, for example, those based on hydroxides, carboxylates, amines,imines, and amides. In an embodiment, a useful quencher is an amine, anamide, or a combination comprising at least one of the foregoing.Preferably, such quenchers include C1-30 organic amines, imines, oramides, or may be a C₁₋₃₀ quaternary ammonium salt of a strong base(e.g., a hydroxide or alkoxide) or a weak base (e.g., a carboxylate).Examples of quenchers include amines such as Troger's base, a hinderedamine such as diazabicycloundecene (DBU) or diazabicyclononene (DBN),N-protected amines such asN-t-butylcarbonyl-1,1-bis(hydroxymethyl)-2-hydroxyethylamine (TBOC-TRIS), or ionic quenchers including quaternary alkyl ammonium saltssuch as tetrabutylammonium hydroxide (TBAH) or tetrabutyl ammoniumlactate.

Other components of the photoresist may include solvents andsurfactants.

Solvents generally suitable for dissolving, dispensing, and coating thecomponents include anisole, alcohols including ethyl lactate,1-methoxy-2-propanol, and 1-ethoxy-2 propanol, esters includingn-butylacetate, 1-methoxy-2-propyl acetate, methoxyethoxypropionate,ethoxyethoxypropionate, ketones including cyclohexanone and 2-heptanone,and a combination comprising at least one of the foregoing solvents.

Surfactants include fluorinated and non-fluorinated surfactants, and arepreferably non-ionic. Exemplary fluorinated non-ionic surfactantsinclude perfluoro C₄ surfactants such as FC-4430 and FC-4432surfactants, available from 3M Corporation; and fluorodiols such asPOLYFOX PF-636, PF-6320, PF-656, and PF-6520 fluorosurfactants fromOmnova.

The photoresist composition disclosed herein includes the photoacidgenerator in the photoresist composition in an amount of 0.01 to 30 wt%, preferably 0.1 to 20 wt %, and more preferably 0.5 to 15 wt %, basedon the total weight of solids. The polymer may be included in an amountof 50 to 99 wt %, preferably 55 to 95 wt %, more preferably 60 to 90 wt%, and more preferably 65 to 90 based on the total weight of solids. Itwill be understood that “polymer” used in this context of a component ina photoresist may mean the acid sensitive polymer or copolymer, or acombination of polymers or copolymers and any other polymer useful in aphotoresist. A surfactant may be included in an amount of 0.01 to 5 wt%, preferably 0.1 to 4 wt %, and more preferably 0.2 to 3 wt %, based onthe total weight of solids. A quencher may be included in relativelysmall amounts of for example, from 0.03 to 5 wt % based on the totalweight of solids. Other additives may be included in amounts of lessthan or equal to 30 wt %, preferably less than or equal to 20%, or morepreferably less than or equal to 10%, based on the total weight ofsolids. The total solids content for the photoresist composition may be0.5 to 50 wt %, preferably 1 to 45 wt %, more preferably 2 to 40 wt %,and more preferably 5 to 35 wt %, based on the total weight of solidsand solvent. It is understood that the solids include polymer, photoacidgenerator, quencher, surfactant, and any optional additives, exclusiveof solvent.

The photoresist composition disclosed herein may be used to form a filmcomprising the photoresist, where the film on the substrate constitutesa coated substrate. Such a coated substrate includes: (a) a substratehaving one or more layers to be patterned on a surface thereof; and (b)a layer of the photoresist composition over the one or more layers to bepatterned. Preferably, patterning is carried out using ultravioletradiation at wavelength of less than 248 nm, and in particular, at 193nm. Preferably, a patternable film comprises the photoacid generator.

Substrates may be any dimension and shape, and are preferably thoseuseful for photolithography, such as silicon, silicon dioxide,silicon-on-insulator (SOI), strained silicon, gallium arsenide, coatedsubstrates including those coated with silicon nitride, siliconoxynitride, titanium nitride, tantalum nitride, ultrathin gate oxidessuch as hafnium oxide, metal or metal coated substrates including thosecoated with titanium, tantalum, copper, aluminum, tungsten, alloysthereof, and combinations thereof. Preferably, the surfaces ofsubstrates herein include critical dimension layers to be patternedincluding, for example, one or more gate-level layers or other criticaldimension layer on the substrates for semiconductor manufacture. Suchsubstrates may preferably include silicon, SOI, strained silicon, andother such substrate materials, formed as circular wafers havingdimensions such as, for example, 200 mm, 300 mm, or larger in diameter,or other dimensions useful for wafer fabrication production.

Further, a method of forming an electronic device includes (a) applyinga layer of a photoresist composition including the photoacid generatorcompound on a surface of the substrate; (b) patternwise exposing thephotoresist composition layer to activating radiation; and (c)developing the exposed photoresist composition layer to provide a resistrelief image.

Applying may be accomplished by any suitable method, including spincoating, spray coating, dip coating, doctor blading, or the like.Applying the layer of photoresist is preferably accomplished byspin-coating the photoresist in solvent using a coating track, in whichthe photoresist is dispensed on a spinning wafer. During dispense, thewafer may be spun at a speed of up to 4,000 rpm, preferably from about500 to 3,000 rpm, and more preferably 1,000 to 2,500 rpm. The coatedwafer is spun to remove solvent, and baked on a hot plate to removeresidual solvent and free volume from the film to make it uniformlydense.

Patternwise exposure is then carried out using an exposure tool such asa stepper, in which the film is irradiated through a pattern mask andthereby is exposed patternwise. The method preferably uses advancedexposure tools generating activating radiation at wavelengths capable ofhigh resolution including 193 nm immersion lithography, in whichexposure using the activating radiation decomposes the PAG in theexposed areas, generating acid and decomposition by-products. The acidthen effects a chemical change in the polymer (e.g., deblocking the acidsensitive group to generate a base-soluble group, or alternatively,catalyzing a cross-linking reaction in the exposed areas).

The invention is further illustrated by the following examples. Allcompounds and reagents used herein are available commercially exceptwhere a procedure is provided below.

Triphenylsulfonium1,1,2,2-tetrafluoro-4-(((-3-hydroxyadamantan-1-yl)methoxy)sulfonyl)butane-1-sulfonate(TPS AdOH-STFBS) was synthesized in five steps as described below.

In the first step, the synthesis of PAG Intermediate Compound 1 (Sodium4-bromo-3,3,4,4-tetrafluorobutane-1-sulfonate) was carried out asfollows. A 250 mL round bottom flask was charged with1,4-dibromo-1,1,2,2-tetrafluorobutane (50.00 g, 174 mmol), 87 mLdeionized water, 87 mL n-butanol, and 24.12 g (191 mmol) sodium sulfite,and the mixture was heated to reflux and stirred under nitrogen for 6days, at which time heat was removed and the reaction cooled to lessthan reflux temperature while standing to separate the phases. Theaqueous phase was separated from the organic (n-butanol containing)phase, extracted with additional n-butanol (2×50 mL), and the organicphases were combined and reduced to 50 mL total volume by rotaryevaporation under reduced pressure. The resulting white slurry wasstirred rapidly and 400 mL methyl t-butyl ether (MTBE) was added. Theslurry was then stirred an additional 15 min and the solids collected byvacuum filtration. The resulting white solid was washed with MTBE, anddried in vacuo at ambient temperature overnight, to yield 62.73 g of theintermediate as a white solid, which was used in the next step withoutfurther purification.

In the second step, the synthesis of PAG Intermediate Compound 2(4-Bromo-3,3,4,4-tetrafluorobutane-1-sulfonyl chloride) was carried outas follows. A 500 mL round bottom flask was charged with 28.61 g ofcrude sodium 4-bromo-3,3,4,4-tetrafluorobutane-1-sulfonate (PAGIntermediate Compound 1) and 92 mL thionyl chloride. The thicksuspension was stirred at ambient temperature under nitrogen until gasevolution ceased, then 450 μL N,N-dimethylformamide (DMF) was added.Stirring was continued at ambient temperature until gas evolutionceased, then the reaction was heated to reflux with stirring undernitrogen for 16 hours. Unreacted thionyl chloride was removed by rotaryevaporation, the residue was dissolved in 400 mL dichloromethane, andthe resulting dichloromethane solution was washed with deionized water(400 mL),and dried over MgSO₄. The dichloromethane solvent was removedby rotary evaporation at 30° C., and the residual oil dried in vacuo atambient temperature for 3 hours, to yield 21.35 g of PAG intermediatecompound 2 as a clear yellow oil.

In the third step, the synthesis of PAG Intermediate Compound 3(3-hydroxyadamantan-1-ylmethyl4-bromo-3,3,4,4-tetrafluorobutane-1-sulfonate; AdOH STFBBr) was carriedout as follows. To a 1 L round bottom flask was added 12.02 g (65.9mmol) of 3-(hydroxymethyl)adamantan-1-ol in 280 mL acetonitrile and 5.61mL (69 4 mmol) pyridine by stirring and warming The reaction was cooledand 4-bromo-3,3,4,4-tetrafluorobutane-1-sulfonyl chloride (PAGIntermediate Compound 2; 21.35 g, 69.4 mmol) was added dropwise to therapidly stirred warm solution, followed by quantitative transfer of anyresidues by rinsing the flask with acetonitrile (2×10 mL). The reactionwas stirred at ambient temperature under nitrogen for 16 hours, at whichtime the solvent was removed under reduced pressure and the residual oilstirred with 500 mL of isopropyl acetate. The resulting whiteprecipitate was removed by vacuum filtration, and the filter cake washedwith minimal isopropyl acetate. The isopropyl acetate filtrates werecombined and washed with 1 N HCl and saturated aqueous NaHCO₃ (200 mLeach), dried over MgSO₄, and the solvent removed under reduced pressureto give 29.55 g of PAG Intermediate Compound 3 as a white solid whichwas used without further purification.

In the fourth step, the synthesis of PAG Intermediate Compound 4(1,1,2,2-tetrafluoro-4-((3-hydroxyadamantan-1-yl)methoxy)sulfonyl)butane-1-sulfonate)was carried out as follows. In a 1 L round bottom flask was dissolvedintermediate compound 1-3 (29.55 g, 65.2 mmol) in 140 mL acetonitrile.Sodium dithionite (17.03 g, 97.8 mmol) and sodium bicarbonate (8.22 g,97.8 mmol) were combined and dissolved in 150 mL deionized water. Theaqueous solution was then added to the stirred acetonitrile solution andthe reaction stirred at ambient temperature under nitrogen for 16 hours.Additional charges of each of sodium dithionite (17.03 g, 97.8 mmol) andsodium bicarbonate (8.22 g, 97.8 mmol) were combined and dissolved inanother 150 mL deionized water and added to the reaction, and thereaction stirred for an additional 20 hours. Reaction monitoring by ¹⁹FNMR indicated 75% completion (molar basis). The reaction was stirredunder nitrogen at 70° C. 16 hours. Reaction completion was confirmed by¹⁹F NMR. Acetonitrile (160 mL) was then added to the reaction, theaqueous phase was saturated with NaCl, and the reaction was stirredrapidly for 30 minutes to homogenize it. The phases were separated andthe aqueous phase extracted with acetonitrile (2×300 mL). Theacetonitrile phases were combined and the solvent removed to give 32.39g crude sulfinate intermediate, which was dissolved in 100 mL deionizedwater and 200 mL acetonitrile. To the stirred solution was addedNa₂WO₄.2H₂O (21 mg, 65 μmol) followed by H₂O₂ (30 w/w % aqueous, 14.82g, 130.4 mmol). The reaction was stirred at ambient temperature for 64hours.

The reaction was then cooled using an ice bath, and sodium bisulfite(10.18 g, 97.8 mmol) was added with stirring. After 10 minutes the icebath was removed, the reaction was saturated with NaCl, and stirredrapidly for 1 hour to homogenize it. The phases were then separated andthe aqueous phase extracted with 250 mL acetonitrile. The solvent of thecombined organic phases was removed by rotary evaporation, the resultingresidue redissolved in 250 mL acetonitrile and filtered by vacuumfiltration and washed with 100 mL acetonitrile. The filtrate wasevaporated on the rotary evaporator at 40° C. to give a clear gum, whichwas dissolved in 50 mL acetonitrile and poured slowly into 3 L ofrapidly stirred methyl t-butyl ether (MTBE). The supernatant wasdecanted and the solids dried under vacuum to yield 17.0 g of the PAGIntermediate Compound 4 as a white solid.

In the fifth step, the synthesis of the PAG compound triphenylsulfonium1,1,2,2-tetrafluoro-4-4(-3-hydroxyadamantan-1-yl)methoxy)sulfonyl)butane-1-sulfonate(TPS AdOH-STFBS) was carried out as follows. To a stirred mixture of 200mL dichloromethane and 200 mL deionized water was added Na AdOH STFBS(intermediate compound 1-4; 17.0 g, 35.7 mmol) and triphenylsulfoniumbromide (11.64 g, 33.9 mmol). The biphasic mixture was stirred undernitrogen at ambient temperature for 10 hours, at which time the phaseswere separated. The organic phase was washed with 18 mΩ deionized water(2×200 ml). Additional dichloromethane (200 mL) was added to the organicphase to promote separation, and the organic phase was then washed withadditional deionized water (4×200 mL). The organic phase was thenfiltered through heavy pleated filter paper, and the solvent removed byrotary evaporation at 30° C. The resulting residue was dissolved in 50mL dichloromethane and poured slowly into 2 L of rapidly stirred methylt-butyl ether. The suspension was then stirred 1 hour, during which timeit congealed and was allowed to stand 30 minutes. The solids were thenvacuum filtered, washed with MTBE, and dried in vacuo to yield 18.05 g(68%) of TPS AdOH-STFBS as a white solid.

The TPS AdOH-STFBS photoacid generator compound of the above example wasthen evaluated lithographically.

The photoresists were formulated using the components and proportionsshown in Table 1, below.

A photoresist polymer (A1) for use in the lithographic evaluations(below) is prepared using monomers M1-M5 below, according to thefollowing procedure.

A solution of 1-ethylcyclopentyl methacrylate (ECPMA, M1; 20 mmol),1-isopropyl-adamantanyl methacrylate (IAM, M2; 20 mmol),2-oxo-tetrahydro-furan-3-yl methacrylate (α-GBLMA, M3; 30 mmol),3-oxo-4,10-dioxa-tricyclo[5.2.1.02,6]dec-8(or 9)-yl methacrylate(ODOTMA, M4; 20 mmol), and 3-hydroxy-adamantanyl methacrylate (HAMA, M5;10 mmol) dissolved in 30 g of tetrahydrofuran (THF) is degassed bybubbling with nitrogen and charged to a 500 ml flask equipped with acondenser, nitrogen inlet and mechanical stirrer along with anadditional 10 g of degassed THF. The solution is brought to reflux, and6 g of dimethyl-2,2-azodiisobutyrate is dissolved in 5 g of THF andcharged in to the flask. The polymerization mixture is then stirred forabout 4 hours at reflux, after which time the reaction is diluted with 5g of THF and the polymerization mixture cooled to room temperature. Thepolymer is precipitated by addition to 1.0 L of isopropanol, collectedby filtration, re-precipitated by dissolving in 50 g THF and addition toanother 1.0 L isopropanol, and collected and dried under vacuum at 45°C. for 48 h. to yield photoresist polymerpoly(IAM/ECPMA/α-GBLMA/ODOTMA/HAMA). Mw=8,000.

The photoresist was formulated using the components and proportionsshown in Table 1 to provide a photoresist and a comparative photoresist.Note that for each, the PAG (see table), base(t-butyloxycarbonyl-4-hydroxypyridine, TBOC-4HP), and surface levelingagent (SLA; also referred to as surfactant; PF 656, available fromOmnova), are shown as a weight percentage based on the total solidscontent of the photoresist, with the balance of the solids being thepolymer. The photoresists are further formulated using as solventspropylene glycol methyl ether acetate (S1) and methyl2-hydroxyisobutyrate (S2) in a 1:1 ratio by weight. The photoresist andcomparative photoresist were each diluted to a final solids of 4 wt %.Photoresist formulation compositions for the comparative example 1(comparative photoresist) and example 1 (photoresist prepared using TPSAdOH-STFBS), are shown in Table 1 below:

TABLE 1 Polymer PAG Base SLA Example (wt %) PAG (wt %) (wt %) ((wt %)CEx. 1 89.29 Triphenylsulfonium 9.58 1.03 0.1 perfluorobutane sulfonateEx. 1 86.66 TPS AdOH-STFBS 12.21 1.03 0.1

Photoresists from Example 1 and Comparative Example 1 werelithographically processed as follows.

The photoresist was spin coated onto a 200 mm silicon wafer having anorganic antireflective coating (AR™77, Rohm and Haas ElectronicMaterials LLC, baked at) and baked at 110° C. for 60 seconds, to form aresist film 100 nm in thickness. The photoresist was exposed with ArFexcimer laser radiation (193 nm) using an ASML/1100 exposure tool(manufactured by ASML) with a numerical aperture (NA) of 0.75, underannular illumination with outer/inner sigma of 0.89/0.64 and focusoffset/step 0.10/0.05. A line-space pattern mask targeting a linewidthof 90 nm and a pitch of 180 nm was used to image the features.

The patterned resist was post exposure baked (PEB) at 100° C. for 60seconds followed by development with 0.26N aqueous tetramethylammoniumhydroxide (TMAH) solution and subsequent water wash. For each example,an L/S pattern having a line width of 90 nm and a pitch of 180 nm wasformed. Mask Error Factor (MEF) and Exposure Latitude (EL) weredetermined by top-down scanning electron microscopy (SEM) using imagescaptured with a Hitachi 9380 CD-SEM, operating at an acceleratingvoltage of 800 volts (V), a probe current of 8.0 picoamperes (pA), and200 K× magnification. Exposure latitude (EL) was defined as a differencein exposure energy to print +/−10% of the target diameter normalized bythe sizing energy. Mask Error Factor (MEF) was defined as the ratio ofcritical dimension (CD) change for the resolved photoresist pattern tothe relative dimension change on the mask pattern.

Results from lithographic evaluation of formulations from ComparativeExample 1 and Example 1 are shown in Table 2.

TABLE 2 Example Esize (mJ/cm²) MEF EL @ 10% of CD Target CEx. 1 23.373.51 10.29 Ex. 1 41.62 3.02 13.66

As seen in Table 2, a photoresist formulation (Ex. 1) prepared using theexemplary sulfonate PAG TPS SAdOH-TFBS above shows a higher exposurelatitude (13.66) and a lower MEF (3.02) when compared with the nearlyidentical comparative photoresist formulation (CEx. 1;l EL 10.29, MEF3.51) but prepared using the commercially available PAGtriphenylsulfonium perfluorobutane sulfonate. Thus, Example 1 whichincludes the PAG TPS SAdOH-TFBS shows the improved lithographicperformance based on exposure latitude (EL) and mask error factor (MEF).

All ranges disclosed herein are inclusive of the endpoints, and theendpoints are independently combinable with each other. The suffix “(s)”as used herein is intended to include both the singular and the pluralof the term that it modifies, thereby including at least one of thatterm. “Optional” or “optionally” means that the subsequently describedevent or circumstance can or cannot occur, and that the descriptionincludes instances where the event occurs and instances where it doesnot. As used herein, “combination” is inclusive of blends, mixtures,alloys, or reaction products. All references are incorporated herein byreference.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the invention (especially in the context of thefollowing claims) are to be construed to cover both the singular and theplural, unless otherwise indicated herein or clearly contradicted bycontext. Further, it should further be noted that the terms “first,”“second,” and the like herein do not denote any order, quantity, orimportance, but rather are used to distinguish one element from another.

The invention claimed is:
 1. A compound having the formula (I): [A-(CHR¹)_(p)]_(k)-(L)-(CH₂)_(m)—(C(R²)₂)_(n)—SO₃ ⁻Z⁺  (I) wherein A is a substituted or unsubstituted, polycyclic, or fused polycyclic C₅ or greater cycloaliphatic group optionally comprising O, S, N, F, or a combination comprising at least one of the foregoing, R¹ is H, a single bond, or a substituted or unsubstituted C₁₋₃₀ alkyl group, wherein when R¹ is a single bond, R¹ is covalently bonded to a carbon atom of A, each R² is independently H, F, or C₁₋₄ fluoroalkyl, wherein at least one R² is not hydrogen, L is a linking group comprising a sulfonate group, a sulfonamide group, or a C₁₋₃₀ sulfonate or sulfonamide-containing group, Z⁺ is an organic or inorganic cation, and p is an integer of 0 to 10, k is 1 or 2, m is an integer of 2-10, and n is an integer of 1 to
 10. 2. The compound of claim 1, having the formula (IIa) or (IIb): A-(CHR¹)_(p)—O—SO₂—(CH₂)_(m)—(C(R²)₂)_(n)—SO₃ ⁻Z⁺  (IIa) A-(CHR¹)_(p)—SO₂—O—(CH₂)_(m)—(C(R²)₂)_(n)—SO₃ ⁻Z⁺  (IIb) wherein A, R¹, R² p, m, n, and Z⁺ are as defined for formula (I).
 3. The compound of claim 1, having the formula (IIIa) or (IIIb): A-(CHR¹)_(p)—N(R³)—SO₂—(CH₂)_(m)—(C(R²)₂)_(n)—SO₃ ⁻Z⁺  (IIIa) A-(CHR¹)_(p)—SO₂—N(R³)—(CH₂)_(m)—(C(R²)₂)_(n)—SO₃ ⁻Z⁺  (IIIb) wherein A, R¹, R² p, m, n, and Z⁺ are as defined for formula (I) and R³ is H, a C₁₋₂₀ alkyl group, or A-(CHR¹)_(p)—.
 4. The compound of claim 1, having the formula (IV), (V), (VI), (VII), (VIII), (IX), (X), (XI), or (XII):

wherein Z⁺ is as defined in formula (I).
 5. The compound of claim 1, wherein Z⁺ is a cation of the formula (XIII):

wherein R⁴ and R⁵ are independently substituted or unsubstituted C₁₋₂₀ alkyl, C₁₋₂₀ fluoroalkyl, C₃₋₂₀ cycloalkyl, C₃₋₂₀ fluorocycloalkyl, C₂₋₂₀ alkenyl, C₂₋₂₀ fluoroalkenyl, C₆₋₂₀ aryl, C₆₋₂₀ fluoroaryl, C₅₋₂₀ heteroaryl, C₇₋₂₀ aralkyl, C₇₋₂₀ fluoroaralkyl, C₆₋₂₀ heteroaralkyl, where R⁴ and R⁵ are separate or connected by a single bond, and Ar is a C₅₋₃₀ aromatic-containing group.
 6. The compound of claim 5, wherein the cation is of the formula (XIV), (XV), or (XVI):

wherein R⁴ and R⁵ are independently substituted or unsubstituted C₁₋₂₀ alkyl, ₁₋₂₀ fluoroalkyl, C₃₋₂₀ cycloalkyl, C₃₋₂₀ fluorocycloalkyl, C₂₋₂₀ alkenyl, C₂₋₂₀ fluoroalkenyl, C₆₋₂₀ aryl, C₆₋₂₀ fluoroaryl, C₅₋₂₀ heteroaryl, C₇₋₂₀ aralkyl, C₇₋₂₀ fluoroaralkyl, or C₆₋₂₀ heteroaralkyl, where R⁴ and R⁵ are separate or connected by a single bond; R⁶, R⁷, R⁸ and R⁹ are each independently H, a halogen, C₁₋₂₀ alkyl, C₁₋₂₀ fluoroalkyl, C₁₋₂₀ alkoxy, C₁₋₂₀ fluoroalkoxy, C₁₋₂₀ thioalkoxy, C₁₋₂₀ fluorothioalkoxy, C₁₋₂₀ alkoxycarbonyl, C₁₋₂₀ fluoroalkoxycarbonyl, C₁₋₂₀ thioalkoxycarbonyl, C₁₋₂₀ fluorothioalkoxycarbonyl, C₃₋₂₀ cycloalkyl, C₃₋₂₀ fluorocycloalkyl, C₃₋₂₀ cycloalkoxy, C₃₋₂₀ fluorocycloalkoxy, C₂₋₂₀ alkenyl, C₂₋₂₀ fluoroalkenyl, C₆₋₂₀ aryl, C₆₋₂₀ fluoroaryl, C₆₋₂₀ aryloxy, C₆₋₂₀ fluoroaryloxy, C₅₋₂₀ heteroaryl, C₅₋₂₀ heteroaryloxy, C₅₋₂₀ heteroaryloxy, C₇₋₂₀ aralkyl, C₇₋₂₀ fluoroaralkyl, C₇₋₂₀ aralkyloxy C₇₋₂₀ fluoroaralkyloxy, or C₆₋₂₀ heteroaralkyl, or C₆₋₂₀ heteroaralkyloxy, wherein R⁶, R⁷, R⁸ and R⁹ are each independently unsubstituted or further substituted to include an acid-labile group, a base-labile group, or a base-soluble group, and q is an integer of 1 to 5, r is an integer of 0 to 3, s is an integer of 0 to 4, t is an integer of 0 to 4, and a is an integer of 0 to
 4. 7. The compound of claim 6, wherein Z⁺ is of the formula (XVII), (XVIII), (XIX), or (XX):

wherein R¹⁰, R¹¹, R¹² and R¹⁴ are independently H, a halogen, C₁₋₁₀ alkyl, C₁₋₁₀ fluoroalkyl, C₁₋₁₀ alkoxy, C₁₋₁₀ fluoroalkoxy, C₃₋₁₀ cycloalkyl, C₃₋₁₀ fluorocycloalkyl, C₃₋₁₀ cycloalkoxy, or C₃₋₁₀ fluorocycloalkoxy, R¹³ is H, C₁₋₁₀ alkyl, C₁₋₁₀ fluoroalkyl, C₃₋₁₀ cycloalkyl, or C₃₋₁₀ fluorocycloalkyl, and a and b are each independently 1 or
 2. 8. A photoresist composition, comprising: an acid-sensitive polymer, and a compound of claim
 1. 9. A coated substrate, comprising: (a) a substrate having one or more layers to be patterned on a surface thereof; and (b) a layer of a photoresist composition of claim 8 over the one or more layers to be patterned.
 10. The coated substrate of claim 9, wherein the compound of claim 1 has the formula (IIa) or (IIb): A-(CHR¹)_(p)—O—SO₂—(CH₂)_(m)—(C(R²)₂)_(n)—SO₃ ⁻Z⁺  (IIa) A-(CHR¹)_(p)—SO₂—O—(CH₂)_(m)—(C(R²)₂)_(n)—SO₃ ⁻Z⁺  (IIb) wherein A, R¹, R² p, m, n, and Z⁺ are as defined for formula (I).
 11. The coated substrate of claim 9, wherein the compound of claim 1 has the formula (IIIa) or (IIIb): A-(CHR¹)_(p)—N(R³)—SO₂—(CH₂)_(m)—(C(R²)₂)_(n)—SO₃ ⁻Z⁺  (IIIa) A-(CHR¹)_(p)—SO₂—N(R³)—(CH₂)_(m)—(C(R²)₂)_(n)—SO₃ ⁻Z⁺  (IIIb) wherein A, R¹, R² p, m, n, and Z⁺ are as defined for formula (I), and R³ is H, a C₁₋₂₀ alkyl group, or A-(CHR¹)_(p)—.
 12. The coated substrate of claim 9, wherein the compound of claim 1 has the formula (IV), (V), (VI), (VII), (VIII), (IX), (X), (XI), or (XII):

wherein Z⁺ is as defined in formula (I).
 13. The coated substrate of claim 9, wherein, in the compound of claim 1, Z⁺ is a cation of the formula (XIII):

wherein R⁴ and R⁵ are independently substituted or unsubstituted C₁₋₂₀ alkyl, C₁₋₂₀ fluoroalkyl, C₃₋₂₀ cycloalkyl, C₃₋₂₀ fluorocycloalkyl, C₂₋₂₀ alkenyl, C₂₋₂₀ fluoroalkenyl, C₆₋₂₀ aryl, C₆₋₂₀ fluoroaryl, C₅₋₂₀ heteroaryl, C₇₋₂₀ aralkyl, C₇₋₂₀ fluoroaralkyl, C₆₋₂₀ heteroaralkyl, where R⁴ and R⁵ are separate or connected by a single bond, and Ar is a C₅₋₃₀ aromatic-containing group.
 14. The coated substrate of claim 13, wherein the cation is of the formula (XIV), (XV), or (XVI):

wherein R⁴ and R⁵ are independently substituted or unsubstituted C₁₋₂₀ alkyl, C₁₋₂₀ fluoroalkyl, C₃₋₂₀ cycloalkyl, C₃₋₂₀ fluorocycloalkyl, C₂₋₂₀ alkenyl, C₂₋₂₀ fluoroalkenyl, C₆₋₂₀ aryl, C₆₋₂₀ fluoroaryl, C₅₋₂₀ heteroaryl, C₇₋₂₀ aralkyl, C₇₋₂₀ fluoroaralkyl, or C₆₋₂₀ heteroaralkyl, where R⁴ and R⁵ are separate or connected by a single bond; R⁶, R⁷, R⁸ and R⁹ are each independently H, a halogen, C₁₋₂₀ alkyl, C₁₋₂₀ fluoroalkyl, C₁₋₂₀ alkoxy, C₁₋₂₀ fluoroalkoxy, C₁₋₂₀ thioalkoxy, C₁₋₂₀ fluorothioalkoxy, C₁₋₂₀ alkoxycarbonyl, C₁₋₂₀ fluoroalkoxycarbonyl, C₁₋₂₀ thioalkoxycarbonyl, C₁₋₂₀ fluorothioalkoxycarbonyl, C₃₋₂₀ cycloalkyl, C₃₋₂₀ fluorocycloalkyl, C₃₋₂₀ cycloalkoxy, C₃₋₂₀ fluorocycloalkoxy, C₂₋₂₀ alkenyl, C₂₋₂₀ fluoroalkenyl, C₆₋₂₀ aryl, C₆₋₂₀ fluoroaryl, C₆₋₂₀ aryloxy, C₆₋₂₀ fluoroaryloxy, C₅₋₂₀ heteroaryl, C₅₋₂₀ heteroaryloxy, C₅₋₂₀ heteroaryloxy, C₇₋₂₀ aralkyl, C₇₋₂₀ fluoroaralkyl, C₇₋₂₀ aralkyloxy C₇₋₂₀ fluoroaralkyloxy, or C₆₋₂₀ heteroaralkyl, or C₆₋₂₀ heteroaralkyloxy, wherein R⁶, R⁷, R⁸ and R⁹ are each independently unsubstituted or further substituted to include an acid-labile group, a base-labile group, or a base-soluble group, and q is an integer of 1 to 5, r is an integer of 0 to 3, s is an integer of 0 to 4, t is an integer of 0 to 4, and a is an integer of 0 to
 4. 15. The photoresist of claim 8, wherein the compound of claim 1 has the formula (IIa) or (IIb): A-(CHR¹)_(p)—O—SO₂—(CH₂)_(m)—(C(R²)₂)_(n)—SO₃ ⁻Z⁺  (IIa) A-(CHR¹)_(p)—SO₂—O—(CH₂)_(m)—(C(R²)₂)_(n)—SO₃ ⁻Z⁺  (IIb) wherein A, R¹, R² p, m, n, and Z⁺ are as defined for formula (I).
 16. The photoresist of claim 8, wherein the compound of claim 1 has the formula (IIIa) or (IIIb): A-(CHR¹)_(p)—N(R³)—SO₂—(CH₂)_(m)—(C(R²)₂)_(n)—SO₃ ⁻Z⁺  (IIIa) A-(CHR¹)_(p)—SO₂—N(R³)—(CH₂)_(m)—(C(R²)₂)_(n)—SO₃ ⁻Z⁺  (IIIb) wherein A, R¹, R² p, m, n, and Z⁺ are as defined for formula (I), and R³ is H, a C₁₋₂₀ alkyl group, or A-(CHR¹)_(p)—.
 17. The photoresist of claim 8, wherein the compound of claim 1 has the formula (IV), (V), (VI), (VII), (VIII), (IX), (X), (XI), or (XII):

wherein Z⁺ is as defined in formula (I).
 18. The photoresist of claim 8, wherein, in the compound of claim 1, Z⁺ is a cation of the formula (XIII):

wherein R⁴ and R⁵ are independently substituted or unsubstituted C₁₋₂₀ alkyl, C₁₋₂₀ fluoroalkyl, C₃₋₂₀ cycloalkyl, C₃₋₂₀ fluorocycloalkyl, C₂₋₂₀ alkenyl, C₂₋₂₀ fluoroalkenyl, C₆₋₂₀ aryl, C₆₋₂₀ fluoroaryl, C₅₋₂₀ heteroaryl, C₇₋₂₀ aralkyl, C₇₋₂₀ fluoroaralkyl, C₆₋₂₀ heteroaralkyl, where R⁴ and R⁵ are separate or connected by a single bond, and Ar is a C₅₋₃₀ aromatic-containing group.
 19. The photoresist of claim 18, wherein the cation is of the formula (XIV), (XV), or (XVI):

wherein R⁴ and R⁵ are independently substituted or unsubstituted C₁₋₂₀ alkyl, C₁₋₂₀ fluoroalkyl, C₃₋₂₀ cycloalkyl, C₃₋₂₀ fluorocycloalkyl, C₂₋₂₀ alkenyl, C₂₋₂₀ fluoroalkenyl, C₆₋₂₀ aryl, C₆₋₂₀ fluoroaryl, C₅₋₂₀ heteroaryl, C₇₋₂₀ aralkyl, C₇₋₂₀ fluoroaralkyl, or C₆₋₂₀ heteroaralkyl, where R⁴ and R⁵ are separate or connected by a single bond; R⁶, R⁷, R⁸ and R⁹ are each independently H, a halogen, C₁₋₂₀ alkyl, C₁₋₂₀ fluoroalkyl, C₁₋₂₀ alkoxy, C₁₋₂₀ fluoroalkoxy, C₁₋₂₀ thioalkoxy, C₁₋₂₀ fluorothioalkoxy, C₁₋₂₀ alkoxycarbonyl, C₁₋₂₀ fluoroalkoxycarbonyl, C₁₋₂₀ thioalkoxycarbonyl, C₁₋₂₀ fluorothioalkoxycarbonyl, C₃₋₂₀ cycloalkyl, C₃₋₂₀ fluorocycloalkyl, C₃₋₂₀ cycloalkoxy, C₃₋₂₀ fluorocycloalkoxy, C₂₋₂₀ alkenyl, C₂₋₂₀ fluoroalkenyl, C₆₋₂₀ aryl, C₆₋₂₀ fluoroaryl, C₆₋₂₀ aryloxy, C₆₋₂₀ fluoroaryloxy, C₅₋₂₀ heteroaryl, C₅₋₂₀ heteroaryloxy, C₅₋₂₀ heteroaryloxy, C₇₋₂₀ aralkyl, C₇₋₂₀ fluoroaralkyl, C₇₋₂₀ aralkyloxy C₇₋₂₀ fluoroaralkyloxy, or C₆₋₂₀ heteroaralkyl, or C₆₋₂₀ heteroaralkyloxy, wherein R⁶, R⁷, R⁸ and R⁹ are each independently unsubstituted or further substituted to include an acid-labile group, a base-labile group, or a base-soluble group, and q is an integer of 1 to 5, r is an integer of 0 to 3, s is an integer of 0 to 4, t is an integer of 0 to 4, and a is an integer of 0 to
 4. 20. The photoresist of claim 19, wherein Z⁺ is of the formula (XVII), (XVIII), (XIX), or (XX):

wherein R¹⁰, R¹¹, R¹² and R¹⁴ are independently H, a halogen, C₁₋₁₀ alkyl, C₁₋₁₀ fluoroalkyl, C₁₋₁₀ alkoxy, C₁₋₁₀ fluoroalkoxy, C₃₋₁₀ cycloalkyl, C₃₋₁₀ fluorocycloalkyl, C₃₋₁₀ cycloalkoxy, or C₃₋₁₀ fluorocycloalkoxy, R¹³ is H, C₁₋₁₀ alkyl, C₁₋₁₀ fluoroalkyl, C₃₋₁₀ cycloalkyl, or C₃₋₁₀ fluorocycloalkyl, and a and b are each independently 1 or
 2. 21. A compound having the formula (IV), (V), (VI), (VII), (VIII), (IX), (X), (XI), or (XII):

wherein Z′ is as defined in formula (I).
 22. A photoresist composition comprising: an acid-sensitive polymer, and a compound having the formula (IV), (V), (VI), (VII), (VIII), (IX), (X), (XI), or (XII):

wherein Z′ is as defined in formula (I). 